Novel, simple, and ultra low-cost single-junction photoanodes consisting of highly-oriented black nanopyramid-arrays of Bismuth(III) Sulfide (i.e. Bi 2 S 3) grown at low temperature by all-solution chemistries onto common, inexpensive and industry-friendly 304 stainless steel show remarkable performance for photoelectrochemical solar water splitting without any co-catalysts. The applied bias photoconversion efficiency (ABPE) reaches 6% on stainless steel at 0.85V vs RHE and photocurrent densities of ~20 and ~45 mA/cm2 at 1.23V vs RHE at 1 and 2 Sun, respectively in aqueous Na 2 S/NaSO 3 solutions due to highly efficient anisotropic charge separation at the apex of the nanopyramids which results in the generation of 0.8 mol h-1 of H 2 per gram of Bi 2 S 3 photocatalysts. Image 1 [ABSTRACT FROM AUTHOR]